1. Field of the Invention
The present invention relates to a casing structure of a flat panel display apparatus (FPD), and more particularly to a chassis structure of the FPD and a mounting form of electric components.
2. Description of the Related Art
FIG. 7 illustrates a conventional casing structure of an FPD which uses a display panel such as a plasma display panel (PDP). At an end of a display panel 701, a flexible circuit board 702 is electrically connected to a leader line from wiring lines formed into a matrix in the panel via an anisotropic conductive film. On a side opposed to a side of the flexible circuit board 702 connected to the display panel 701, a driver board 703 that includes an electric circuit mounted thereon to control driving is electrically connected. A driver integrated circuit (IC) is mounted on each block of the flexible circuit board 702. A number of wiring lines of the flexible circuit board 702 connected to the driver board 703 side is fewer than that connected to the display panel 701 side. The driver board 703 is electrically connected to a control board 704 on which a control circuit is mounted. A number of wiring lines of the driver board 703 connected to the control board 704 is less than that connected to the flexible circuit board 702.
Generally, the display panel 701 and a chassis 705 are fixed to each other by an adhesive. The driver board 703 and the control board 704 are fixed to the backside of the chassis 705 by screws. The driver board 703 is arranged near each side of the display panel 701 since the driver board 703 is electrically and mechanically connected to the display panel 701 via the flexible circuit board 702. The flexile circuit board 702 is expensive, and thus its length has a considerable effect on overall costs of the apparatus.
Japanese Patent Application Laid-Open No. 2006-65120 discusses that a conductive plate for connecting a driving circuit board and a flat display panel with each other includes a bent part extending in a direction along a side face of the display panel. A length of a flexible circuit board can be shortened by connecting the bent part of the conductive plate and an end of the flexile wiring board to which a reinforcing board is fixed, overlapping one another.
A display panel having a large area can use a chassis of a multi-layered structure to maintain strength of the chassis.
However, in the case of the conventional casing structure, the flexible circuit board cannot be sufficiently shortened when the chassis has a multi-layered structure.
As illustrated in FIG. 8, generally, a front cover arranged to surround a peripheral part of a display surface is fixed to flange portions 801 formed at four corners of the chassis by screws. Each flange portion 801 is formed in a position such that the flexible circuit board 702 is not pinched when the front cover is bonded with the flange portions 801.
In the case of the display panel having a large area, fixing the panel only by the flange portions 801 arranged at the four corners provides no satisfactory connection strength. Therefore, the number of flange portions has to be increased. FIG. 9 illustrates an exemplary method for increasing the number of flange portions. According to this method, a large space is set between adjacent flexible circuit boards 702 to arrange a flange portion 706 therein. Thus, even if the flexible circuit board 702 is bent to the backside of the chassis, the chassis and the front cover can be properly fixed together.
In the case of a display panel having high resolution, however, unlike the case of FIG. 9, it is difficult to secure a sufficient space between flexible circuit boards because of an increase in the number of wiring lines.
The present invention is directed to providing a casing structure suited to a display panel of a large area and high resolution.